To add to the confusion: For 2 weeks/year I help out the local ballet studio with stage crew. We have this big white backdrop curtain, and colorful lights are pointed directly at the curtain to make dramatic and moody changes to the background during certain dances. When I heard the name of these, I assumed it was the "psyche curtain" and "psyche lights" because that's how it is pronounced.

Turns out the box is marked "Cyc." I have to assume that the people that sold the curtain are way less amateur than I am, so I would like to add this third potential spelling.